[OPEN] Mouse scrolling on a grid scrolls both horizontally and vertically

I'm starting to get worryingly familiar with submitting bug reports.

REQUIRED INFORMATION

Ext version tested:

Ext 4.0.2a

Browser versions tested against:

FF3.6

Chromium 14

Description:

When you scroll all the way to the bottom-right of a grid with both horizontal and vertical bars visible, then scroll up, it scrolls BOTH the horizontal and vertical bars at the same time. The horizontal then KEEPS scrolling to the left regardless of whether or not you scroll up or down.